A large amount of olefin polymers adhering to a polymerization reactor is a source of troubles for operating a production process of olefin polymers. Therefore, it is desirable that an amount of olefin polymers adhering thereto is as small as possible. From such a viewpoint, it is preferable that olefin polymer powders obtained by olefin polymerization have the following particle properties: high in their bulk density, small in their content of fine powders, narrow in their particle size distribution, and excellent in their fluidity.
U.S. Pat. No. 4,672,050 (corresponding to JP 61-218606A) discloses an α-olefin polymerization catalyst, which is high in its polymerization activity, hardly decreases stereoregularity during polymerization, and makes only a small amount of by-product amorphous polymer, and which catalyst is formed by a process comprising the steps of (i) contacting a solid catalyst component precursor with an ester compound, an ether compound and titanium tetrachloride, thereby obtaining a trivalent titanium compound-containing solid catalyst component, and (ii) contacting the obtained catalyst component with an organoaluminum compound and an electron donor compound (third component).
U.S. Pat. No. 6,187,883 (corresponding to JP 10-212312A) discloses an α-olefin polymerization catalyst, which is high in its polymerization activity, and makes only a very small amount of by-product amorphous polymer, and which catalyst is formed by a process comprising the steps of (i) reducing a titanium compound by an organomagnesium compound in the presence of a silicon compound and an ester compound, thereby obtaining a solid catalyst component precursor, (ii) contacting the obtained precursor with a halogenating compound, an electron donor and an organic acid halide, thereby obtaining a trivalent titanium compound-containing solid catalyst component, and (iii) contacting the obtained catalyst component with an organoaluminum compound and an electron donor compound (third component).
U.S. Pat. No. 6,903,041 (corresponding to JP 11-322833A) discloses an olefin polymerization catalyst, which is very excellent in its particle properties, is high enough in its polymerization activity, and makes only a small amount of low molecular weight polymer components, and which catalyst is formed by a process comprising the steps of (i) contacting a solid catalyst component precursor, a halogen-containing compound of Group 14 elements and an electron donor, with one another, then (ii) further contacting with titanium tetrachloride, thereby obtaining a solid catalyst component, and (iii) combining the obtained catalyst component with an organoaluminum compound.